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Kan Wang, Gengping Wan, Guilong Wang, Zhengyi He, Shaohua Shi, Lihong Wu, Guizhen Wang
The demand for microwave absorbing materials with strong absorption capability and wide absorption band is increasing due to serious electromagnetic interference issues and defense stealth technology needs. Here the carbon-coated Fe3O4 (Fe3O4@C) yolk-shell composites were successfully synthesized in a large scale for the application of microwave absorption through an in-situ reduction process from carbon-coated γ-Fe2O3 precursor. The results show that the Fe3O4 nanoparticles are uniformly coated with a thin carbon layer about 10nm in thickness and a clear void about 1 nm in width between Fe3O4 core and carbon shell are formed due to the volume shrinkage during the reduction treatment...
October 6, 2017: Journal of Colloid and Interface Science
Aaron M Coffey, Roman V Shchepin, Bibo Feng, Raul D Colon, Ken Wilkens, Kevin W Waddell, Eduard Y Chekmenev
Applications of parahydrogen induced polarization (PHIP) often warrant conversion of the chemically-synthesized singlet-state spin order into net heteronuclear magnetization. In order to obtain optimal yields from the overall hyperpolarization process, catalytic hydrogenation must be tightly synchronized to subsequent radiofrequency (RF) transformations of spin order. Commercial NMR consoles are designed to synchronize applied waves on multiple channels and consequently are well-suited as controllers for these types of hyperpolarization experiments that require tight coordination of RF and non-RF events...
September 30, 2017: Journal of Magnetic Resonance
Antoine Bierret, Grégory Vincent, Julien Jaeck, Jean-Luc Pelouard, Riad Haïdar, Fabrice Pardo
We present a theoretical study of the mid-infrared guided mode resonance spectral filters made of two subwavelength metallic gratings and a dielectric waveguide under a focused beam with a finite spot size. This Letter shows that, at the resonant wavelength, the lateral extension of the electromagnetic field in the waveguide is close to the width of the beam. We compare the performance of filters using gratings with a one-slit pattern and gratings with a two-slit pattern, and we show that the latter gratings (biatom gratings) provide a higher transmission and a better limitation of field extension, due to an improved angular acceptance...
October 15, 2017: Optics Letters
Alexander K Popov, Sergey A Myslivets
We propose metamaterial (MM) that supports a mixture of three or more normal and backward electromagnetic modes with equal co-directed phase velocities and mutually contra-directed energy fluxes. This enables extraordinary three-wave mixing, greatly enhanced optical parametric amplification, and frequency-changing generation of entangled photons in the reflection direction. Proof-of-principle numerical simulation of such processes is presented based on the particular example of the wave-guided terahertz waves contra-propagating in the MM made of carbon nanotubes...
October 15, 2017: Optics Letters
X Garcia-Santiago, S Burger, C Rockstuhl, I Fernandez-Corbaton
We present an electromagnetic chirality measure for 2D arrays of subwavelength periodicities under normal illumination. The calculation of the measure uses only the complex reflection and transmission coefficients from the array. The measure allows the ordering of arrays according to their electromagnetic chirality, which further allows a quantitative comparison of different design strategies. The measure is upper bounded, and the extreme properties of objects with high values of electromagnetic chirality make them useful in both near- and far-field applications...
October 15, 2017: Optics Letters
Stijn Debruyne, Nicolas Grognard, Gino Verleye, Korneel Van Massenhove, Dimitrios Mavreas, Bart Vande Vannet
BACKGROUND: Implant stability testing at various stages of implant therapy by means of resonance frequency analysis is extensively used. The overall measurement outcome is a function of the resulting stiffness of three entities: surrounding bone, bone-implant complex, and implant-Smartpeg complex. The influence of the latter on the overall measurement results is presently unknown. It can be investigated in vitro by use of imbedded implants with mounted Smartpegs. This enables to keep the influence of the two other entities constant and controlled...
October 12, 2017: International Journal of Implant Dentistry
Maria Koutsoupidou, Evangelos Groumpas, Irene S Karanasiou, Maria Christopoulou, Konstantina Nikita, Nikolaos Uzunoglu
Microwave radiometry is a passive technique used to measure in-depth temperature distributions inside the human body, potentially useful in clinical applications. Experimental data imply that it may provide the capability of detecting in-depth local variations of temperature and/or conductivity of excitable tissues at microwave frequencies. Specifically, microwave radiometry may allow the real-time monitoring of brain temperature and/or conductivity changes, associated with local brain activation. In this paper, recent results of our ongoing research regarding the capabilities of focused microwave radiometry for brain intracranial applications are presented...
October 13, 2017: Medical & Biological Engineering & Computing
Murat Çetkin, Can Demirel, Neşe Kızılkan, Nur Aksoy, Hülya Erbağcı
BACKGROUND: Electromagnetic fields (EMF) created by mobile phones during communication have harmful effects on different organs. OBJECTIVES: It was aimed to investigate the effects of an EMF created by a mobile phone on serum iron level, ferritin, unsaturated iron binding capacity and total iron binding capacity within a rat experiment model. METHODS: A total of 32 male Wistar albino rats were randomly divided into the control, sham, mobile phone speech (2h/day) and stand by (12 h/day) groups...
March 2017: African Health Sciences
Li-An Wu, Wei-En Li, Ding-Zheng Lin, Yih-Fan Chen
We demonstrate three-dimensional surface-enhanced Raman spectroscopy (SERS) substrates formed by accumulating plasmonic nanostructures that are synthesized using a DNA-assisted assembly method. We densely immobilize Au nanoparticles (AuNPs) on polymer beads to form core-satellite nanostructures for detecting molecules by SERS. The experimental parameters affecting the AuNP immobilization, including salt concentration and the number ratio of the AuNPs to the polymer beads, are tested to achieve a high density of the immobilized AuNPs...
October 12, 2017: Scientific Reports
Majid Jadidi, Mahfouzeh Sadat Khatami, Fatemeh Mohammad-Pour, Afsaneh Bandavi, Ali Rashidy-Pour, Abbas Ali Vafaei, Abbas Ali Taherian, Hossein Miladi-Gorji
This study examined the effects of low frequency magnetic field (MF) on tolerance to analgesic effect of morphine in rats. Rats were made tolerant to morphine by injecting morphine (10 mg/kg, s) once daily for 8 consecutive days. Rats were simultaneously exposed to an MF (50 Hz at 1, 50, and 100 μT for 30 min) before, immediately, or 30 min after injection of morphine, and also exposed to a 0.5, 6, 12, and 30 Hz at 100 μT for 30 min before injection of morphine. The percentage of maximum possible effect of morphine (% MPE) was measured on the 1st, 4th, and 8th days by hot plate test...
October 11, 2017: Bioelectromagnetics
Ezra E Smith, James F Cavanagh, John J B Allen
Frontal EEG alpha asymmetry provides a promising index of depression risk, yet very little is known about the neural sources of alpha asymmetry. To identify these sources, this study examined alpha asymmetry using a distributed inverse solution: exact low resolution brain electromagnetic tomography (eLORETA). Findings implicated a generator in lateral midfrontal regions that contributed to both surface asymmetry and depression risk. Participants with any lifetime history of depressive episodes were characterized by less left than right activity in the precentral gyrus and midfrontal gyrus...
October 11, 2017: Psychophysiology
Gangil Byun, Hosung Choo
One of the most challenging problems in recent antenna engineering fields is to achieve highly reliable beamforming capabilities in an extremely restricted space of small handheld devices. In this paper, we introduce a new perspective on single-radiator multiple-port (SRMP) antenna to alter the traditional approach of multiple-antenna arrays for improving beamforming performances with reduced aperture sizes. The major contribution of this paper is to demonstrate the beamforming capability of the SRMP antenna for use as an extremely miniaturized front-end component in more sophisticated beamforming applications...
2017: PloS One
Mahsa Mohammadi-Zadeh Khoshroo, Mehdi Shamsaie Mehrjan, Farzaneh Samiee, Mehdi Soltani, Seyed Pezhman Hosseini Shekarabi
Increasing of anthropogenic electromagnetic fields in aquatic environments has been recently become the core of attention. In this study, the effect of extremely low-frequency electromagnetic fields (50 Hz) on immune status and metabolic markers of common carp fingerling was assessed. The fish were exposed to extremely low-frequency electromagnetic fields at four intensities of 0.1, 0.5, 1, and 2 mT only once for 2 h; then, they were reared for 60 days. Results showed that the levels of aspartate aminotransferase (AST) and alanine transaminase (ALT) and alkaline phosphatase (ALP) were increased with an increase in the electromagnetic field intensity on 15 and 60 days post exposure...
October 11, 2017: Fish Physiology and Biochemistry
Kwon-Seok Chae, Yong-Hwan Kim
Throughout the long history of various therapeutic trials of transcranial magnetic stimulation (TMS), some TMS protocols have been reported to be clearly effective in the treatment of neurodegenerative diseases. Despite promising results from repetitive TMS (rTMS) using low frequency electromagnetic fields (EMFs) for neurodegenerative diseases, the low reproducibility has hampered the clinical applications of rTMS. Here, based on the notion of radical pair mechanism explaining magnetoreception in living organisms, we propose a new perspective that rTMS with controlled geomagnetic field (rTMS-GMF) can be an efficient and reproducible therapeutic approach for neurodegenerative diseases...
2017: Frontiers in Human Neuroscience
T Yokouchi, N Kanazawa, A Kikkawa, D Morikawa, K Shibata, T Arima, Y Taguchi, F Kagawa, Y Tokura
Chirality of matter can produce unique responses in optics, electricity and magnetism. In particular, magnetic crystals transmit their handedness to the magnetism via antisymmetric exchange interaction of relativistic origin, producing helical spin orders as well as their fluctuations. Here we report for a chiral magnet MnSi that chiral spin fluctuations manifest themselves in the electrical magnetochiral effect, i.e. the nonreciprocal and nonlinear response characterized by the electrical resistance depending on inner product of current and magnetic field...
October 11, 2017: Nature Communications
Kenjiro Iwasa, Reddi A Hari
BACKGROUND: Bone and cartilage joint formation, maintenance and regeneration are regulated by both chemical and physical signals. Among the physical signals there is increasing realization of the role of Pulsed electromagnetic fields (PEMF) in the treatment of nonunions of bone fractures. The discovery of the piezoelectric properties of bone by Fukada and Yasuda in 1953 in Japan established the foundation of this field. Pioneering research by Bassett and Brighton and their teams resulted in the approval by Food and Drug Administration (FDA) the use of PEMF in treatment of fracture healing...
October 12, 2017: Tissue Engineering. Part B, Reviews
Una Bergin, Richard M Lynch
ECG interpretation is an essential skill in the management of the acutely unwell patient and in addition to history taking and physical examination has been shown to have a significant effect on referral patterns to cardiologists. One of the basic initial steps in ECG interpretation is assessment for the presence of artefact which if present can dramatically influence the diagnosis. The most common sources of artefact are tremor e.g. in Parkinson’s disease, loose skin electrodes and electromagnetic interference from other medical devices and mobile phones...
February 2017: Practitioner
Cesar Elosua, Francisco Javier Arregui, Ignacio Del Villar, Carlos Ruiz-Zamarreño, Jesus M Corres, Candido Bariain, Javier Goicoechea, Miguel Hernaez, Pedro J Rivero, Abian B Socorro, Aitor Urrutia, Pedro Sanchez, Pablo Zubiate, Diego Lopez-Torres, Nerea De Acha, Joaquin Ascorbe, Aritz Ozcariz, Ignacio R Matias
The measurement of chemical and biomedical parameters can take advantage of the features exclusively offered by optical fibre: passive nature, electromagnetic immunity and chemical stability are some of the most relevant ones. The small dimensions of the fibre generally require that the sensing material be loaded into a supporting matrix whose morphology is adjusted at a nanometric scale. Thanks to the advances in nanotechnology new deposition methods have been developed: they allow reagents from different chemical nature to be embedded into films with a thickness always below a few microns that also show a relevant aspect ratio to ensure a high transduction interface...
October 11, 2017: Sensors
Yu-Mi Kim, Sang-Eun Cho, Soo-Chan Kim, Hyun-Joon Jang, Young-Kwon Seo
This study evaluated frequency-dependent effects of extremely low frequency electromagnetic fields (ELF-EMFs) on melanogenesis by melanocytes in vitro. Melanocytes were exposed to 2 mT EMFs at 30-75 Hz for 3 days before melanogenesis was examined. Exposure to ELF-EMFs at 50 and 60 Hz induced melanogenic maturation without cell damage, without changing cell proliferation and mitochondrial activity. Melanin content and tyrosinase activity of cells exposed to 50 Hz were higher than in controls, and mRNA expression of tyrosinase-related protein-2 was elevated relative to controls at 50 Hz...
October 11, 2017: International Journal of Molecular Sciences
Ana Paula Bispo Silva, Jamily Alves da Silva
Phenomena involving electromagnetism and conservation of energy during the nineteenth century did not fit the reigning Newtonian paradigm. Among scholars, there was the need to explain such facts considering "something more" that had not yet been expressed. Through this explanation, Naturphilosophie, the philosophical branch associated with the German romantic movement of the nineteenth century, seems to offer new ways of understanding the sciences. In this article, we present main aspects of the work of Schelling, the main exponent of Naturphilosophie, and how his assumptions were inserted into the physical sciences to explain electromagnetism and conservation of energy...
July 2017: História, Ciências, Saúde—Manguinhos
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